[PATCH 06/15] ipvs: no need to reroute anymore on DNAT over loopback

[Simon Horman <horms@xxxxxxxxxxxx>]

From: Julian Anastasov <ja@xxxxxx>

After commit 70e7341673 (ipv4: Show that ip_send_reply()
is purely unicast routine.) we do not need to reroute DNAT-ed
traffic over loopback because reply uses iph daddr and not
rt_spec_dst.

Signed-off-by: Julian Anastasov <ja@xxxxxx>
Signed-off by: Hans Schillstrom <hans@xxxxxxxxxxxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
 net/netfilter/ipvs/ip_vs_xmit.c |   58 ++-------------------------------------
 1 file changed, 2 insertions(+), 56 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 6448a2e..c942d36 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -207,44 +207,6 @@ __ip_vs_get_out_rt(struct sk_buff *skb, struct ip_vs_dest 
*dest,
        return rt;
 }
 
-/* Reroute packet to local IPv4 stack after DNAT */
-static int
-__ip_vs_reroute_locally(struct sk_buff *skb)
-{
-       struct rtable *rt = skb_rtable(skb);
-       struct net_device *dev = rt->dst.dev;
-       struct net *net = dev_net(dev);
-       struct iphdr *iph = ip_hdr(skb);
-
-       if (rt_is_input_route(rt)) {
-               unsigned long orefdst = skb->_skb_refdst;
-
-               if (ip_route_input(skb, iph->daddr, iph->saddr,
-                                  iph->tos, skb->dev))
-                       return 0;
-               refdst_drop(orefdst);
-       } else {
-               struct flowi4 fl4 = {
-                       .daddr = iph->daddr,
-                       .saddr = iph->saddr,
-                       .flowi4_tos = RT_TOS(iph->tos),
-                       .flowi4_mark = skb->mark,
-               };
-
-               rt = ip_route_output_key(net, &fl4);
-               if (IS_ERR(rt))
-                       return 0;
-               if (!(rt->rt_flags & RTCF_LOCAL)) {
-                       ip_rt_put(rt);
-                       return 0;
-               }
-               /* Drop old route. */
-               skb_dst_drop(skb);
-               skb_dst_set(skb, &rt->dst);
-       }
-       return 1;
-}
-
 #ifdef CONFIG_IP_VS_IPV6
 
 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
@@ -635,16 +597,8 @@ ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
                /* drop old route */
                skb_dst_drop(skb);
                skb_dst_set(skb, &rt->dst);
-       } else {
+       } else
                ip_rt_put(rt);
-               /*
-                * Some IPv4 replies get local address from routes,
-                * not from iph, so while we DNAT after routing
-                * we need this second input/output route.
-                */
-               if (!__ip_vs_reroute_locally(skb))
-                       goto tx_error;
-       }
 
        IP_VS_DBG_PKT(10, AF_INET, pp, skb, 0, "After DNAT");
 
@@ -1269,16 +1223,8 @@ ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn 
*cp,
                /* drop the old route when skb is not shared */
                skb_dst_drop(skb);
                skb_dst_set(skb, &rt->dst);
-       } else {
+       } else
                ip_rt_put(rt);
-               /*
-                * Some IPv4 replies get local address from routes,
-                * not from iph, so while we DNAT after routing
-                * we need this second input/output route.
-                */
-               if (!__ip_vs_reroute_locally(skb))
-                       goto tx_error;
-       }
 
        /* Another hack: avoid icmp_send in ip_fragment */
        skb->local_df = 1;
-- 
1.7.10.4

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